Pest control active ingredients have been and are currently blended with polymers such as polyvinyl chloride and then shaped into forms such as strips, animal collars and animal ear tags for use in controlling pests. See, for example, U.S. Pat. Nos. 3,318,769, 3,852,416 and 4,150,109. A principle disadvantage of the prior art polymer/active ingredient blends is that a considerable amount of the active ingredient is not released by the blend and is unavailable for the control of the target pest. This factor reduces the cost effectiveness and useful life of the product. Another disadvantage of prior art polymer/active ingredient blends is that the .rate of release of active ingredient from the blends not uniform which results in less efficient use of the active ingredient. The present invention overcomes the aforementioned drawbacks of the prior art blends (systems).
Many pest control active ingredients are irritants to warm blooded animals (including humans). This irritation to the skin and/or eyes of warm blooded animals hampers the use of pest control active ingredients. This irritation factor occurs even when the pest control active ingredient is blended with polymers or, in other formulations, such as granules, dusts, dips, liquids, emulsions, etc., wherein the active ingredient is considerably diluted. The present invention overcomes or significantly reduces the irritation to warm blooded animals of pest control ingredients.